1. 4th International Conference on Transportation Infrastructure (ICTI)
Laboratory Evaluation of Road Construction Materials Enhanced with Nano-Modified Emulsions (NMEs)
4th International Conference on Transportation Infrastructure (ICTI)
I Akhalwaya and FC Rust
9 July 2018

2. Overview Brief Introduction to Nanotechnology
Standard Bitumen Emulsions vs NMEs
CSIR Laboratory Results and Discussions
Concluding Remarks
The way forward for NMEs

3. Introduction What is Nanotechnology?
Lots of misconceptions about nanotechnology

4. Definition of Nanotechnology
Simplest Definition:
“Nanotechnology is the next biggest thing that's really small” – Unknown
Scientific Definition:
“Nanotechnology may be defined as the term used to cover the design, construction and utilisation of functional structures with at least one characteristic dimension measured in nanometres (nm)” - Kelsall et.al (2005)

5. Relative scale of a Nanometre (nm)
What potential impact does this have?
- (Justin Kavanagh, 2017)
Tennis Ball =
1 Nanometre
Earth = 1 Metre

6. Chemistry of Standard Bitumen Emulsions
Bitumen Particle
Bitumen Particle +
Emulsifying Agents
Sea of Water Molecules (Blue Shading)

7. Standard Emulsifier of a Bitumen Emulsion
Non-Polar Tail (hydrophobic and lipophilic)
Polar Head (hydrophilic and lipophobic)
Single Janus Particle of a traditional bitumen emulsifier

8. What is a Nano-Modified Emulsion (NME)?
NME = Standard Bitumen Emulsion + Nano-additives
Types of nano-additives found in NMEs:
Combination of Nano-Polymers and/or Organo-Silanes
Provides extremely low-viscosities.
Provides a NME material with hydrophobic properties
It improves the distribution and coverage which allows for smaller quantities of residual bitumen to be used

9. How do NMEs Work?

10. Visual Representation of a Siloxane surface
Water droplets were coloured in blue for visual presentation

11. Visual Hydrophobic Test
Standard Bitumen Sample after 3 hours
NME Sample after 3 hours

12. Laboratory Investigation: Materials Tested
X-Ray Diffraction (XRD) Results of Raw materials
17-20% Mica (Muscovite) and a
7-43% clay minerals (Smectite/Kaolinite)
i,e. marginal quality materials
“Independent material tests showed the material was not suitable for cement stabilisation as they were unable to achieve the minimum strength requirements with the specified cement quantity”
Source: Jordaan et al. (2017a)

13. The Common Norm in this Scenario VS NMEs
Imported high quality granular base and subbase layers
High-Costs
Exorbitant Transportation costs of hauling large quantities of materials, especially from further distances..
or alternatively:
Stabilisation using a standard bitumen emulsion
High percentages of stabilising agent will be needed to meet design criteria – High Costs
Or ideally the best scenario:
Stabilisation using a NME

14. Benefits of NMEs applicable To This Scenario
• Improved performances
• Required design strength is obtained using low percentages of residual bitumen as well as nano-additives
• Enables the use of locally available marginal materials and at lower risk
• Improved resistance to water damage due to the rejection of the water from the bitumen-aggregate bonding process
Source: Jordaan et al. (2017b)

15. Sample Description for Strength Tests
Sample Description, Information and Properties
Stabilising Agent
SS60 anionic nano-modified emulsion (NME) with organo-silane and nano-polymer additives
Standard SS60 anionic emulsion without any additives
% of stabilising agent added
0.7% per mass
% of cement content
None
Optimum Moisture Content (OMC) %
6.0
Sample Diameter (mm)
150mm Ф Sample

16. Laboratory Results
SS60 anionic nano-modified emulsion (NME) with organo-silane and nano-polymer additives
Standard SS60 anionic emulsion without any additives
Test Performed
UCS** (Dry)
UCS (Wet)
ITS*** (Dry)
ITS (Wet)
UCS (Dry)
ITS (Dry)
Average (kPa)
2430
1923
179
158
2218
558
145 36
NME Equivalent Classification (Jordaan et al. 2017b)
NME2
Not suitable for NME treatment due to materials not meeting any specification
BSM* Equivalent Classification (TG2, 2009)
BSM2
Not suitable for BSM treatment due to materials not meeting any specification
*Bituminous Stabilised Material (BSM)
**Unconfined Compressive Strength (UCS)
*** Indirect Tensile Strength (ITS)

17. Summary and Discussion of Results
UCS Dry - 10% increase in strength
UCS Wet - 244% increase in strength
ITS Dry - 23% increase in strength
ITS Wet - 338% increase in strength
Performs extremely well under wet conditions relative to standard bitumen emulsions
Limitation in terms of results displayed for Standard Bitumen Emulsion

18. Concluding Remarks
Lot of misconceptions about the use of nanotechnology, including NMEs – attend the NME seminars and workshops
Preliminary tests indicate that NME materials perform significantly superior to traditional bituminous stabilised materials
The required design strengths obtained exceeded expectation using low percentages of stabilisation agent
The overall laboratory evaluation concludes that NMEs may in fact be used to enable the cost-effective use of locally available marginal materials at lower risk, which may have direct implications for improved cost-effective pavement design alternatives in the future
So does mean that NMEs are better?

19. The Way Forward for NMEs
Performance Testing
Full-scale Laboratory Programme needed with more specialised laboratory studies needed
Heavy Vehicle Simulator (HVS) tests on NME trial projects to verify laboratory results
Economic Studies
Economic models and Life-Cycle Cost Analysis
Environmental Studies
Risk Evaluation studies and Environmental Impact Assessments (EIAs)

20. Where do NMEs currently stand in SA?
HVS testing and continuous Laboratory investigation at the CSIR
International and Local Collaboration
Source: as cited in Steyn (2011)

21. Acknowledgements Prof. Gerrit Jordaan Dr. Louw du Plessis
Mr. Martin Murphy
Mr. Thomas Modise
CSIR Transport Infrastructure Engineering Staff and Laboratory Technicians

22. Thank you!
Questions?
Elsevier